Russian President Vladimir Putin raised a few approving eyebrows in Turkey by quoting from the Koran to urge an end to the war in Yemen that has been waged there for years by a coalition of Muslim countries led by Saudi Arabia.

Speaking in Ankara on Monday alongside Turkey's President Recep Tayyip Erdogan and Iran's President Hassan Rouhani, Putin introduced a particular line from the Muslim holy book, known as the Surah al-Imran.

"And remember the favor of Allah upon you - when you were enemies and He brought your hearts together and you became, by His favor, brothers," the Russian president quoted.

Putin also referenced another Koranic teaching, about how violence is only legitimate in self-defense, to semi-jokingly suggest that Saudi Arabia should buy Russian air defense systems, as Iran and Turkey have already done.

The Russian president's references to the holy text of Islam were noted with approval by both Erdogan and Rouhani, who are Sunni and Shia Muslims, respectively. Both leaders admonished the Saudi-led invasion of Yemen, which has resulted in tens of thousands of deaths over the past five years and has utterly devastated the country on the southern tip of the Arabian peninsula.

What began as a civil war between the rebel Houthis and the Saudi-backed government escalated into an air war led by the Saudis and into a full-blown ground invasion in 2015. The coalition has not managed to defeat the Houthis in over four years, however, as shown by the most recent drone attack on Saudi oil facilities.